Table 2.

Select Features of SLC6A1-Related Neurodevelopmental Disorder

Feature% of Persons w/FeatureComment
Developmental delay >90%Mild to severe
Hypotonia 60%Low muscle tone in infancy is common & improves w/age.
Intellectual disability 35%Mild to severe
Seizures 85%Absence & atypical absence, myoclonic, & atonic seizures are most prevalent. Some persons have intractable epilepsy.
Movement disorders 40%Intermittent tremor w/fine motor tasks & ataxia are most common.
ASD 30%Rigidity, repetitive speech patterns & behaviors, sensory sensitivity, & sensory-seeking behaviors are most common.
ADHD 15%Hyperactive, inattentive, or combined type

ADHD = attention-deficit/hyperactivity disorder; ASD = autism spectrum disorder

From: SLC6A1-Related Neurodevelopmental Disorder

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